Seat tilting chair



United States Patent [72] Inventor Henry Aguilar 1309 27th Ave., SanFrancisco, California 94131 21 Appl. No. 772,262 [22] Filed Oct. 31,1968 [45] Patented Nov. 10, 1970 [54] SEAT TILTING CHAIR 12 Claims, 11Drawing Figs.

[52] U.S. Cl 297/320 [51] Int. Cl A47c U032 [50] Field oiSearch 297/316,320, 338, 345; 5/81 [56] References Cited UNlTED STATES PATENTS 689,942i2/l90l Wright 297/320 3,000,668 9/1961 Croy 3,337,266 8/1967 BurnsPrimary ExaminerReinaldo P. Machado Attorney-Boyken, Mohler, Foster andSchwab ABSTRACT: A chair having a generally horizontally disposed seatpivotally mounted for tilting about an axis parallel with its forwardedge under a continuously applied force of progressively decreasingstrength proportionate to progressive changes in the position of thecenter of gravity of the body of a person rising in a normal manner froma fully seated position on said seat, and which seat is returnable fromtilted position under progressively increasing resistance as the weightof said person is applied to said seat in a normal seating operation.

Patented Nov. 10, 1970 v 3,539,220

INVENTOR. HEMP) Aka/44? lrrdi/vifi SEAT 'IILTING CHAIR SUMMARY Theemployment of electric motors and power transmission means, includinglinks and gears for tilting chair seats, is expensive and addsappreciably to the weight of the chair. Also, in the event of accidentalslippage by the person rising from the chair, and a sudden backwardmovement of such person when the seat is )artially or wholly tilted, mayresult in the person sliding onto the floor, causing injury, since theseat will continue its movement in the direction in which its tiltingmovement is started, or will stop.

Other attempts to solve the problem of assisting persons to rise fromseated positions in chairs without employing a motor, have involved therequirement of one or more manually actuatable levers that are intendedto tilt the seat proportionate to the degree of manual force applied tothe levers, and hydraulic means has been connected to the seat. whichmeans must be manually actuated to provide the force for tilting theseat.

The normal manner in which most persons rise from arm chairs is to leanforward in the chair and to place their hands on the arms of the chairat the same time. This results in movement of the center 'of gravity ofthe body forwardly to approach the position in which the center ofgravity is over the feet and by slight downward pressure of the handsagainst the arms, combined with the employment of the leg muscles, thebody moves to an upright standing position.

Those persons, such as invalids, elderly persons and others, whose legand arm muscles are weakened, normally have little difficulty in risingif some assistance is given to getting the body over the legs, and dueto these weaknesses in the legs and arms, a sudden and unexpectedapplication of force, or lack of such application, may result in seriousinjury unless provision is made for counteracting such application offorce or lack of the latter.

One of the objects of the present invention is the provision of atilting chair seat in a chair that is provided with means arranged andconstructed to automatically be cooperative with the normal actions of aseated person in rising to provide substantial assistance to suchperson, and which means is ofa type that is free from the use ofauxiliary power-driven elements, such as electric motors or the like,and also free from means that must be manually operated to transmitpower to the seat, and an added object is the provision of such chairseat that is readily adapted to use by persons of different weights andstrengths.

A still further object of the present invention is the provi sion of achair adapted to accomplish the foregoing objects, and which chairincludes safety means to prevent accidental and unexpected operation ofthe seat in the event the sitter should make moves that would normallyeffect tilting of the seat when no such tilting was desired.

An additional object is the provision of an armchair in which the seatand back are connected and simultaneously movable, solely under theinfluence ofa force applied thereto, from a normal angular position ofsaid seat and back relative to each other, to a position in which saidseat is tilted about a horizontal axis parallel with its forward edge,until the person that was seated thereon is in a substantially uprightposition or in a position in which the legs are substantially straightand upright, and which force is continuously applied and is ofprogressively decreasing strength proportionate to progressive changesin the center ofgravity of the body ofa person during the act of risingin a normal manner from a fully seated position on said seat, andresting against said back, with the hands of said person resting on thearms of said chair.

Another object of the invention is the provision ofa method of assistinga person seated in an armchair, to rise from the latter, and an addedobject includes the method ofsal'ely seating a standing person.

Other objects and advantages will appear in the description anddrawings.

In the drawings:

FIG. I is a perspective view showing the rear and one side of a chairembodying one form of the invention, minus conventional upholstering ofthe seat and back and arms, or where such upholstering is desired.

FIG. 2 is a view of the chair of FIG. I showing the front and one side.

FIG. 3 is a side-elevational view of the chair of FIG. 1, shown in fullline, and the seat and back are shown in elevated position in brokenlines.

FIG. 4 is a fragmentary enlarged isometric view of a portion of thechair detached from the latter.

. FIG. 5 is a fragmentary enlarged elevational view of a portion of thedevice shown in FIG. 4 detached from the latter, with a portion of thechair shown in cross section.

.FIG. 6 is an isometric view of a portion of the seat lifting device ofthe chair separate from the latter.

FIG. 7 is an elevational view of one of the seat lifting elements ofFIG. 6.

FIG. 8 is an isometric view of a modified form of seat and backelevating structure apart from the chair, except for the seat.

FIGS. 9, ll), ll are diagrammatic views illustrating the manner ofoperation of the invention in successive steps dur ing rising of aperson from the chair, the modified form of the chair being shown forclarity, in which weights are used instead of springs.

DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION The chairillustrated comprises front legs 1 (FIG. 2), rear legs 2, (FIG. 1),front cross frame member 3, upper rear cross frame member 4, (FIG. 1),and a lower rear cross frame member 5. Extending between, and secured tothe front cross frame member 3, and to the lower cross frame member 5,are spaced parallel frame members 6 (FIGS. l3).

A generally horizontally disposed seat 7 has forward extensions 8 (FIG.2) rigid therewith, which extensions are pivotally connected at 9 tobrackets 10 that are secured to the upper ends of legs I. Said seat issupported on the lower frame members 6 when the seat is in its lowermostposition, and conventional upholstery or a cushion, not shown, may bepart of the seat, and secured thereto for movement therewith.

The use of the words forward," forwardly, rearward," and rearwardly,"and words of similar import, are used with reference to the seat andback of the chair against which the back of a person is adapted to rest.Said back is generally designated 13 and extends upwardly from the rearedge of the seat 7. The seat extends forwardly from the lower edge ofthe back 13. The back, like the seat, may be upholsteredin the usualmanner. This invention is not concerned with the type of upholstery, ifany.

The back 13 includes upwardly extending side frame pieces 14, the lowerends of which are pivotally connected to brackets 15 secured to the rearend of seat 7 at opposite sides ofthe latter by coaxial pivots 17 (FIGS.2, 3).

Rigidly connected to the rear ends of the side frame members 6 and toupper cross frame member 4 are a pair of vertically extending uprights18 that terminate at their lower ends adjacent the rear edge of seat 7,and at their upper ends below an upper horizontal piece 19 (FIG. I) onsaid seat, which piece 19 extends between, and is rigid with the upperends of the side pieces 14.

Parallel chair arms 20 extend forwardly past the side pieces 14 of theback 13 and are rigidly secured to the upper ends of legs I and 2, therear ends of said arms projecting rearwardly past the back 13,saidprojeeting rear ends being rigidly connceted by a horizontal backframe member 23, (FIG. I). The forward ends of said arms may projectforwardly of the upper ends of legs I.

The back l3 includes a rigid panel having an upper section 25 (FIG. Ithat is parallel with side pieces 14 along the forward edges of thelatter, and a lower panel 26 that may incline slightly rearwardly in adownward direction from the lower edge of the upper section (FIGS. 2,3).

Said sections 25, 26 extend to and are rigidly connected with the sidepieces 14, and the upper ends of the uprights 18 are rounded at 27 (FIG.3) and slidably support the back I3, the latter being inclinedrearwardly from its lower end when the seat is in its lowermostposition. The forward faces 28 of the upper portions of uprights 18 areinclined to lie flat against the rear side of section 25 when the seatis in said lowermost position, and the rounded upper edges 27 of thepanel 25 uprights I8, is a horizontal cylindrical bar 33 (FIGS. I, 3, 6)

on which is swingably supported the upper end of a flattened housing 34carrying a plurality of sets 3 5 (FIG. 6) of pairs of conventionalspring tension pulleys 37 (FIG. 7) respectively enclosing a spring 38 ofthe clock spring-type each stationarily held at one end and connected atits opposite end with a wire rope or cord 39, shown in single lines inFIGS. I, 6, that is adapted to extend downwardly from the spring of eachpair. A hook 40 is provided at the lower end of each rope 39.

Rotatably carried by, and projecting through, the rear ends of arms(FIGS. 4, 6) is a horizontal bar 43 that, in turn, is parallel with thebar 33 that extends between and is carried by the upper ends of theuprights 18 (FIG. 6). Eye members 45 extending longitudinally of the bar43 project upwardly from the latter and are rigid with and extendlongitudinally thereof. One eye 45 is on each of the projecting endportions of bar 43 that project oppositely outwardly of the pair of arms30, and two corresponding eyes are between the arms30. These eyes arevertically below the sets of spring tension devices so one or both ofthe wire cords 39 may be detachably connected with each eye by a hook40.

The sets 35 of spring tension pulleys are readily available in anydesired strength. Thus the spring in each pulley may exert approximatelya It) pound pull on each cord, when the hook is at the pulley, or more,according to the lifting force desired, the degree of pull beingprogressively increased as each hook is pulled outwardly of the housing34. Thus, the total amount of yield-able tension applied to the ends ofarms 30 depends upon the number of cords connected with bar 43.

When the seat and back of the chair are in the full line posi tion, asseen in FIG. 3, the cords 39 that are connected with g bar 43 will betensioned to the maximum degree for moving the seat and back to thebroken line position 47, in which the seat has swung about pivots 9 andthe back and seat have moved about pivots [7.

When the seat and back are in the broken line position 47 (FIG. 3) it isseen that the springs 38 in sets35 are at their minimum tension (butwhich is still quite substantial) as the bar 43 and the said springs arerelatively close together. The decrease in the lifting power exerted onthe seat by the springs and the mechanical or leverage advantage becomeprogressively less as the seat tilts to its maximum tilted position,said maximum tilted position occurring when the seat 7 and the back aresubstantially in alignment with the cords 39, and at this point thesubstantial force of the spring is fully transferred to the pivots 9.

Supported at the underside of each arm 20 of the chair is ahorizontally-extending rod 49 terminating at its forward end in a button50 (FIGS. 1, 3) readily accessible to the finger of the hand of a personseated in the chair for pushing therod rearwardly by such finger. Eachrod slidably extends through openings in the upper portions of legs 2, 3and through the upper rear cross frame member 4, and terminates at itsrear end rearwardly of cross frame member 4 (FIG. I). The forward end ofeach rod 49 projects forwardly from the upper portion ofeach leg I,

The horizontally aligned bars 51 (FIG. I) of a pair thereof are spacedslightly rearwardly of the upper rear cross frame member 4, each barbeing swingable about a vertical pivot 52 (FIGS. I, 3) supported at itsends by the back frame member 23, and a member 53 rigid with andprojecting rearwardly from the upper cross frame member 4.

The ends of bars 51 (FIG. I) opposite the ends that are engaged by thepush rods 49 terminate centrally between the sides ofthe chair andengage the forward side of the upper end of a generally verticallyextending strip 54. Horizontal coaxial pivots 55 intermediate the upperand lower ends of said strip pivotally support saidspring on a pair ofhorizontally spaced, vertically extending frame members 56, rigidlysecured at their upper ends to the back frame member 23 and to the lowerrear cross frame member 5.

The lower portion.58 (FIGS. 4, 5) of strip 54 is yieldably held inengagement with the rear arcuate surface of a horizontal element 59that, in turn, is secured at its ends against the terminal rear endsurfaces of the arms 30. These arms 30 are the ones that are secured toand extend rearwardly and downwardly from seat 7.

The lower end portion of strip 54 adjacent to and above portion 58thereof, said strip is formed with an upper and a lower pair offorwardly and downwardly projecting teeth 60, the lower pair of whichare spaced above the element 59 (FIG. 5) a distance enabling them toclear said element 59 when the lower end of the strip is movedrearwardly, so that the element 59, and consequently seat 7, may swingupwardly. However, unless said lower end of strip 54 is movedrearwardly, the lower pair of teeth 60 will engage the element 59 toprevent upward movement of the seat. The dotted line position of element59 (FIG. 5) shows the latter in engagement with the lower pair of teeth.

A coil spring 61 (FIG. 3) reacts between the lower portion of strip 54and the lower rear frame member 5 to yieldably urge the lower end 58 ofsaid strip against the arcuate rear side of element 59.

The provision of the teeth 60 and the release means comprising a fingeractuated rod 49 and its connection with strip 54 to release the seat forupward tilting movement, is to prevent accidental tilting of the seat 7,should a person seated in the chair lean forward when not intending torise. The position of the push buttons 50 under both arms, where one mayreadily be pushed rearwardly, by a finger of either hand, when desired,are not accessible to accidental actuation that would likely release theseat for tilting when not intended, and the second, upper pair of teethis to insure against accidental tilting of the seat when a person isbeing seated, but is not fully seated to the degree where the lower setof. teeth are operative for holding the seat down. Some persons, inbeing seated, may shift themselves, and lift their bodies slightly justbefore being fully seated, and with the upper set of teeth 60automatically operative to hold the seat down unless one or the other ofrods 49 are actuated, the person is not unexpectedly given an upwardpush by the seat. Both sets of teeth automatically move to hold-down"positions when the seat is lowered under the weight ofa person.

Substantially the same manner of operation may be effected by thesubstitution of a pulley and weights for the spring sets 35, as shown inFIGS. 811, in which the same numerals will be used for elementscorresponding to those shown in FIGS. 1- -7.

In FIGS. 8-1! a horizontal differential pulley 64 is rotatably supportedbetween the upper ends of upright 18 and arms 30 project downwardly andrearwardly below seat 7.

The central portion 67 (FIG. 8) of pulley 64 is of reduced diameter,while the end portions 68 are of substantially greater diameter. Cords69, secured to and extending around portions 68, depend from saidportions 68 and carry removablc weights 7() at. their lower ends, whilea single cord 7I extends around and is secured to the reduced diametercentral portion 67 of pulley 64 and depends therefrom for connectionwith the bar 72 extending between and connecting the rear ends of arms30 that are connected with seat 7. The seat 7 is pivoted at its forwardend to the chair at 9. A back 13. (FIGS. 9l I corresponding to back I3.may be pivotally connected to the seat 7 by pivots 17. The bar 72. itshould be noted. substitutes for bar 43 in FIG. 6.

The differential pulley 64 and its connection to the seat provides asubstantial power advantage that enables a relatively compactarrangement of weights while applying the desired lifting effect on theseat. and the relationship between the arms and pulley 64 is such thatthe maximum upward force on the seat is applied when the seat is in itslowermost position. corresponding to the full line position of the seat7 in FIG. 3. or in FIGS. 8-l0 while the minimum force is exerted whenthe cord 71 is generally in alignment with the seat. and the seat andback 13 (FIG. 9) are in a position corresponding to the broken lineposition 47 in FIG. 3, or in full line in FIG. 11.

Arms (FIGS. 9- l l) are the same as shown in FIG. 3 and the push rodsand spring and hook structure 49 to 61 are understood to all present inthe form of invention semidiagrammatically illustrated in FIGS. 9--l 1.

In both forms of the invention, the upward force applied to the seat isprogressively reduced as the seat rises. The employment of the sets ofsprings instead of the use of weights substantially reduces the weightof the chair; however, in both forms. the degree of upward force appliedto the seat and back may be quickly and easily varied to suit the weightof the person. and to the degree of lifting force that is desired by thesitter.

Persons using the chair may be elderly and merely weakened to a degreethat their legs lack sufficient strength to lift the body to a standingposition. but are capable of walking. once they have risen. or they maybe partially incapacitated through illness. accident or for otherreasons so that control of the limbs during rising from a chair may besomewhat uncertain. For safety reasons in such instances, a foot pad 76(FIGS. 1, 2) of fabric or suitable material having a roughened uppersurface may be provided for the feet of the user. Openings 77 in saidpad for the lower ends of the front legs 2 of the chair is provided toprevent slippage of the chair rearwardly in the event the chair ispushed rearwardly when the person on the pad is rising or is beingseated. An upturned portion 78 (FIG. I) of the pad at the rear edge ofeach opening will still further prevent accidental rearward slippage ofthe chair and pad. The weight of the person on the pad will hold the paddown.

FIGS. 9. 10, 11 best illustrate the manner of operation of theinvention, whether springs or weights are used to apply the upward forceto the seat 7. The structure employing the pulley 64, cords 69. H andweights 70 is shown in FIGS. 9II for clarity. It is obvious that thespring sets of FIG. 6 may be substituted for the length of cord 71 (FIG.9) that extends between the arms 30 and the pulley 64.

The center ofgravity of a person 80 fully seated in the chair. as seenin FIC. 9 is approximately at line 8I. In an adult. the upper and lowerlegs articulate about a point that is close to the axis of pivots 9. Theforward extensions 8 on the seat 7 position the pivots 9 of the chair atapproximately the level of the knee joints so that the scat legs willswing about approximately the same horizontal axis. The arms 83 of theperson 80 are shown resting on arms 20 ofthe chair.

FIG. 10 shows the initial movement of the person 80 in rising. The upperbody moves forward to gain lifting power in the upper and lower arms andat the same time the center ofgravity moves a substantial distanceforwardly to approximately line 84, (FIG. 10) which is appreciablycloser to pivot 9, with the result of decreasing the degree of forcerequired to tilt the seat to the point where any desired degree oflifting force may be applied according to the number of cords 39 (FIG.6) or weights 70 (FIGS. 8-11) are employed.

In most instances. and for purposes of safety, the springs or weightsare so adjusted that some use of the arms 83 or downward pressure of thehands on arms 20 of the person is desirable to effect a tilting of theseat and to raise the body to the position of FIG. 11 and the liftingforce applied to the seat progressively decreases as the sitter rises toa standing posisively increasing resistance to lowering the seat as theseat moves to the full line position of FIGS. 3, 9 from the position 47of FIG. 3 or the full line position of FIG. ll. Were there no decreasein the lifting power as the seat tilts to the position shown in FIG. 11.and the person using the chair would slip, such person would slide offthe seat and onto the floor. with the likelihood of receiving an injury.

The automatic, gentle return of the seat to its generally horizontalposition solely under the influence of the weight of a person. wherethere is insufficient downward pressure of the hands on the arms of thechair to reduce the gravitational force of the body below the everpresent upward force applied to the seat by the springs or weights,enables the person using the chair to have full control of the operationof the seat at all times.

The automatic progressive reduction in the degree of upward forceapplied to the seat as the center of gravity of the body moves forwarduntil the person is standing. and the automatic progressive increase insaid upward force as the person resumes a seated position insures thesafety of the person using the chair. The body is not propelled upwardlyat a rate of speed that is independent of the desires of the personusing the chair. and at any time during said movement the person may bereseated by merely moving his body from the forward leaning position tothe normal rearward leaning seating position, or by ceasing to exertdownward pressure of the hands on the arms. according to how the springsor weights may be ad justcd.

Normally. where a person is fully seated in an arm chair. the center ofgravity is approximately along a vertical line 81 (FIG. 9), extendinggenerally from or through the horizontal axis of the hip joints 85.although it may vary slightly forwardly or rearwardly of such lineaccording to the erectness of the body of the sitting person.

The lower legs of such sitting person would under any circumstance beapproximately vertical. and the upper legs would be approximately atright angles to the lower legs, and the forearms would restsubstantially horizontally on the rigid arms ofthe chair, with the handsstationary on the latter.

The foregoing is the normal position a seated person, particularly whensuch person were prepared to rise, but had made no movement of the bodyfrom a fully seated position. As applied to a person in substantiallythe foregoing position, the preferred method of elevating such person inaccordance with the present invention, may be said to comprise the stepsof applying an upwardly and forwardly directed force against thebuttocks of the seated person along line 81, which force is insufficientto elevate such person to a standing position. and then progressivelymoving said center of gravity forwardly by bending the body above saidaxis of said hip joints forwardly about said axis whereby the differencebetween the degree of force required to overcome the influence ofgravity and to elevate said person becomes progressively less, and thenovercoming the latter difference by application of a downward pressureof the hands against the arms of said chair while said lower legs remainsubstantially stationary whereby the body of such person willautomatically be elevated to standing position. and at the same timeprogressively decreasing the strength of said upwardly directed forcealong said line.

Insofar as the chair itself is concerned. basically the chair may besaid to comprise a rigid frame having a generally horizontally disposedseat providing a forward and a rear edge. and horizontally extendingarms at opposite sides of said seat adapted to support the hands of aperson seated on said seat with the lower legs of such person extendingacross said forward edge. Pivot means pivotally supports the seat forswinging upwardly about a horizontal axis parallelwith and adjacent tosaid forward edge, and seat elevating means is carried by said frame andconnected with said seat for yield-ably swinging said seat upwardlyabout said axis to a position inclined upwardly from the latter forapplying an upward force against a person seated on said seat forelevating such person to a standing position, and for yieldably holdingsaid seat in said upwardly inclined position preparatory to receivingthe weight of such person upon the latter being reseatcd on said seat.Said elevating means is yieldable, such as the springs or weights, andare variable for application of different degrees of elevating force tosaid seat. This variability may be by connecting more or fewer of thesprings or by increasing or decreasing the weights, or by tensioning orrelaxing one or more springs that connect the seat with the frame.

By the present method and structure, the chair is also readily adjustedto the weight of any person using it, and to the capacity of such personto rise. Once adjusted, the application of the desired forces isautomatic. Actuation of a push rod 49 to release the seat and back, asheretofore mentioned, is a safety measure, although it is apparent thatwhere the user of the chair desires and requires only a smallapplication of force on the seat to tilt the latter, and the weight ofthe body is adequate to prevent actuation of the seat where a suddenforward movement ofthc body occurs, it could be omitted.

There is a normal slight forward push on the feet of a person risingfrom the chair, where the strength ofthc legs is impaired which tends toslide the chair rearwardly. This usually occurs shortly before theperson is in the position shown in FIG. I]. The employment of the pad 75prevents any likelihood ofthe feet or the chair slipping during theoperation of rising, although usually, were the feet or chair to slip,the person would automatically resume a seated position, as hereinbeforementioned.

The absence of a motor, switches, gears, hydraulic means, etc.,heretofore employed, materially reduces the cost of manufacture andsubstantially eliminates maintenance costs.

Although this invention has been described by specific structure, itwill be obvious to one skilled in the art that many modifications may beconstructed without departing from the invention. The scope of thisinvention is defined only in the appended claims.

Iclaim:

l. The method of elevating a person seated in an armchair to a standingposition, and returning such person from a standing position to a seatedposition in such chair, in which seated position the hands of saidperson are on the arms of said chair and the lower legs areapproximately vertical at approximately a right angle to the upper legsat the knee joints with the center of gravity of the body along avertical line that approximately extends through the horizontal axis ofthe hip joints, which method includes the steps of:

a. applying a generally upwardly directed predetermined amount of forceagainst the buttocks of said person along said line, which force issubstantially sufficient to elevate such person from said seatedposition when said center of gravity is moved forwardly relative to saidaxis generally toward said knee joints;

b. progressively moving said center of gravity forwardly by leaning theupper portion of his body forwardly about said axis to the point wheresaid degree of upward force is substantially equal to the force ofgravity, and then elevating his body about said knee joints to astanding position by said person applying a sufficient downward pressureof his hands on the arms of said chair sufficient to steady his bodyduring rising to a standing position and to overcome said force ofgravity;

c. progressively reducing the degree of said upwardly applied forceduring movement of said body to said standing position to apredetermined degree and ceasing the application of said upwardlyapplied force at a predetermined point at said predetermined degree whenthe center of gravity of said body is approximately over the lower legsof said person, and said person is substantially in said standingposition:

d. reapplying said generally upwardly directed force against thebuttocks of said person at said predetermined point at saidpredetermined degree upon said person in said standing position movinghis body to reseat himself in said chair; and

e. progressively moving the center of gravity of the body rearwardlyaway from said knee joints about said axis toward said line by rearwardmovement of the body, and progressively increasing the degree of saidupwardly applied force to an amount approximately equal to but less thansaid force of gravity, until said person is in said seated position,whereby said movements of said body to said standing position and tosaid seated position are under full control of said person at all times.

2. [n a chair that includes a frame having a forward and rear side:

a. a generally horizontally disposed seat for a person disposed betweensaid forward and rear side for seating a person thereon from saidforward side;

b. supporting means on said frame adjacent said forward side supportingsaid seat for upward movement of the rear end of said seat that isopposite to said forward side from a generally horizontal position ofsaid seat to an elevated position in which said seat is inclinedupwardly from said forward sidc relative to horizontal for supportingsuch person approxin' ately in a standing position;

0. seat elevating means con nectcd with said seat for moving the latterfrom said 1101 izontal position with a person seated thereon, to saidelevated position; and

d. said elevating means including power means automatically operativefor applying a progressively diminishing degree of upward force to saidseat for moving said seat from said generally horizontal position tosaid elevated position, when a person is seated thereon.

3. In a chair as defined in claim 2; (e) said power means beingoperative mainly under the influence of changes in the horizontalposition of the center of gravity of a person seated on said seat in adirection toward said forward side.

4. in a chair as defined in claim 3:

f. means for increasing and for decreasing applied by said power meansaccording to the weight of the person seated on said seat, whereby saidupwardly applied force may substantially equal the specific gravity ofsaid person at said center of gravity; and i g. the degree at which saidupwardly applied force diminishes being proportional to the degree ofchange in said horizontal position of the center of gravity of saidperson in a direction toward said forward side of said chair.

5. in a chair as defined in claim 2:

. said power means being continuously operative for applying an upwardforce to said seat, when said seat is generally horizontal with a personseated thereon, to a degree that is insuffieient to elevate said personwhen the center of gravity of said person is over the rear portion ofsaid seat with the upper body of said person upright, and which power issubstantially suffieient to elevate said seat and the person seatedthereon when the center of gravity of said upper body is moved forwardlytoward the forward side of said seat a predetermined distance;

f. manually actuatable means for releasably holding said seat againstupward movement thereof until manual actuation of said last-mentionedmeans.

6. In a chair as defined in claim 5:

g. a back extending upwardly from the rear end of said seat having alower edge pivotally connected with said rear end of said seat; and

h. means supporting said back for upward movement with said seat to aposition generally coplanar with the latter when said seat is in itselevated position.

7. In a chair that includes a frame having a forward and a rear side andgenerally horizontally disposed, horizontally spaced arms inside-by-side relation extending between said the upward force forwardand rear sides for supporting the arms of a person seated in said chair:

a. a generally horizontally disposed seat for a person disposed betweensaid forward and rear side and at a level below that of said arms forsupporting a seated person thereon, said seat having a forward and arear end respectively adjacent said forward and rear sides of saidframe;

h. supporting means on said frame supporting said seat for upwardmovement of said rear end about an axis adjacent said forward end from agenerally horizontal position of said seat to an elevated position inwhich said seat is inclined upwardly from said forward side at asufficient angle relative to horizontal for supporting a person on saidseal in approximately a standing position;

cl yieldable elevating means connected with said scat automaticallyoperative for applying a yieldahle upwardly directed force to said seatsufficient for moving the latter from said generally horizontallyextending position to said elevated position when a person seatedupright on said seat leans his upper body forwardly and applies arelatively slight downward pressure of his hands against said arms, saidyieldable means yieldably supporting said body for automatic downwardmovement of said seat from said elevated position to said generallyhorizontal position upon such person seating himself from a standingposition at said forward side of said frame on said seat substantiallyfree from downward pressure of his hands on said arms, said yieldablemeans being insufficient to hold said seat in said elevated positionunder the full weight of a person; and

d. means for increasing and for decreasing the upward yicldahle forceapplied by said yieldable means according to the weight of the personusing said chair.

in a chair as defined in claim 7:

. said yieldable means comprising springs connected with said seat andframe under yieldable tension at all times for applying said upwardforce to said seat; and

f. means connecting said springs with said frame in a position forprogressively diminishing the upward force applied to said seat duringmovement of the latter to said elevated position, and for progressivelyincreasing the upward force so applied during movement of said seat tosaid generally horizontal position under the weight of a person on saidseat.

. In a chair as defined in claim 8;

. seat holding means on said frame relcasahly connected with said seatfor holding said seat in said generally horizontal position against saidupward movement thereof under the influence of said yieldable meansmovable to a position releasing said seat for said upward movement; and

h. manually actuatahle means operably connected with said seat holdingmeans for releasing the latter from seat holding relation upon manualactuation of said manually ac tuatable means.

10. In a chair as defined in claim 9; (i) said manually actuatable meansbeing adjacent each of the arms of said chair and accessible to the handof either arm of a person seated in said chair for actuation by a fingerof either hand.

(g) in a chair as defined in claim 8: g. said supporting means for saidseat including pivots spaced forwardly of the forward end of said seatfor swinging said seat about a horizontal axis that is approximatelycoaxial with the knee joints of a person fully seated on said seat,whereby a person being elevated to a standing position will not slide onsaid seat during movement to said standing position.

12. In a chair as defined in claim 8; (g) said frame including forwardand rear legs, and a foot support for the feet of a person-seated onsaid chair connected with said front legs to prevent sliding of saidchair relative to said foot support during rising or seating of a personfrom said chair having his feet on said foot support

